Non-Ceramic hard armor composite

ABSTRACT

A hard armor composite includes a rigid non-ceramic facing and a ballistic fabric backing. The fabric backing is carried by the facing, and includes an array of bundled high-performance fibers. The fibers have a tensile strength greater than 7 grams per denier and a denier per filament ratio of less than 5.4.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

This invention relates to a hard armor composite, and more particularlyto an improved small arms protection insert (SAPI) applicable forprotecting against multiple small arms bullets and projectiles. In apreferred embodiment, the invention incorporates a rigid non-ceramicfacing and a ballistic fabric backing.

Ceramic armor is typically used for body armor and for the outercoverings of different types of vehicles, such as various types of landvehicles, ships, and aircraft. Typically, ceramic tiles are adhesivelysecured to a substrate then encapsulated in an outer cover. The armorsystem is then attached to a vehicle by a variety of means or merelyplaced in a fabric pocket, as in the case of body armor. An inherentproblem in the prior art is that ceramic armor is relatively heavy, andis configured for a fixed level of protection against a single ballisticthreat.

The current SAPI incorporates ceramic and an extended chain polyethylenefiber base material known in the industry as “Spectra UnidirectionalCross Plied”. This material contains fibers produced by HoneywellInternational, Inc., and distributed under the brand Spectra Shield® PCRand Spectra Shield® Plus PCR. The current SAPI has been accepted forapplication by the United States military. However, due to limitedproduction and sources of Spectra Shield® PCR and Spectra Shield® PlusPCR, a need exists for an alternative acceptable ballistic fabricconstruction which can be readily obtained from multiple sources.

A further need exists for a reduced-weight SAPI which offers at leastcomparable and preferably increased ballistic performance. Militaryspecifications call for a SAPI which meets predetermined maximum weightand performance criteria. The ballistic fabric used in the current SAPIhas a denier per filament (dpf) ratio of 5.4—denier being defined as aweight measurement in grams per 9000 meter of fiber length; and denierper filament (dpf) defined as denier divided by the number of filamentsin a fiber bundle. For an example, Spectra Shield® PCR comprises anominal 1300 denier fiber with 240 filaments (or, 5.4 dpf). The presentinvention uses a lower dpf fiber which meets or exceeds the requiredballistic performance criteria. The reduced fiber weight combined with alighter, less costly non-ceramic facing forms a novel SAPI superior inregards to both weight and performance. The overall weight of thenon-ceramic SAPI is well below that prescribed by United States militaryspecifications. In addition, the non-ceramic SAPI is easily molded forenhanced curvature, and has improved field durability as compared to aceramic SAPI. The ceramic SAPI is extremely hard and brittle, anddifficult to shape.

SUMMARY OF INVENTION

Therefore, it is an object of the invention to provide a hard armorcomposite which incorporates a non-ceramic rigid facing and fabricbacking including high performance, low denier-per-filament (dpf)fibers. The rigid facing and fabric backing are preferably separatelyformed and subsequently joined together to create the hard armorcomposite. Alternatively, the facing and backing may beintegrally-formed together under heat and pressure in a single stepprocess.

It is another object of the invention to provide a non-ceramic hardarmor composite which offers substantial ballistic performance, isrelatively lightweight, and easily molded for enhanced curvature.

It is another object of the invention to provide a non-ceramic hardarmor composite which enables use of a less costly and lighter facingwithout sacrificing ballistic performance.

It is another object of the invention to provide a non-ceramic hardarmor composite which provides protection against multiple types ofballistic projectiles including NATO 7.62×51 mm-80 Ball, Soviet 7.62mm×54R Ball Type LPS, and U.S. 5.56 mm×M855 Ball.

It is another object of the invention to provide a non-ceramic hardarmor composite which may be used alone or as a supplementary armorsystem to provide increased protection from ballistic projectiles.

It is another object of the invention to provide a non-ceramic smallarms protection insert (SAPI) applicable for being worn by military andlaw enforcement personnel, and which has improved field durability ascompared to a ceramic SAPI.

It is another object of the invention to provide a non-ceramic hardarmor composite which, when placed in a body armor vest pocket, providesballistic protection from 5.56 mm and 7.62 rounds.

It is another object of the invention to provide alternate, lighter, newand useful means of protecting against ballistic projectiles attack.

It is another object of the invention to provide a new and useful meansof constructing a hard armor composite.

It is another object of the invention to provide a new and useful meansof incorporating a composite armor backing with a non-ceramic facing.

These and other objects of the present invention are achieved in thepreferred embodiments disclosed below by providing a hard armorcomposite including a rigid non-ceramic facing and a ballistic fabricbacking. The fabric backing is carried by the facing, and includes anarray of bundled high-performance fibers. The fibers have a tensilestrength greater than 7 grams per denier and a denier per filament ratioof less than 5.4.

The term “carried by” means that the fabric backing is bonded orotherwise secured, either directly or indirectly, to the rigid facing.The term “non-ceramic facing” refers to a rigid facing constructed ofless than 5% ceramic material, and more preferably, without a trace ofceramic material. Preferably, the entire hard armor composite isconstructed without a trace of ceramic material.

According to another preferred embodiment of the invention, the fabricbacking includes a plurality of overlying fabric layers. The fabriclayers may be woven, non-woven, partially non-woven, or knitted.Alternatively, the layers may comprise unidirectional tape which iscross-plied in any angle, or three-dimensional woven or knitted fabrics.

According to another preferred embodiment of the invention, the fabriclayers are laminated under heat and pressure to form a unitary ballisticstructure.

According to another preferred embodiment of the invention, means areprovided for adhering the fabric backing to the rigid facing.

Preferably, the means for adhering is an adhesive selected from thegroup including a thermoplastic polymer resin matrix and a thermosettingpolymer resin matrix.

According to another preferred embodiment of the invention, the meansfor adhering is a polymer film.

According to another preferred embodiment of the invention, the meansfor adhering is an adhesive selected from the group including an epoxyadhesive, a polysulfide adhesive, a polyurethane adhesive, a phenolicadhesive, a polyester adhesive, a polyvinyl butyral adhesive, apolyolefin adhesive, and a vinyl ester adhesive.

According to another preferred embodiment of the invention, the rigidfacing is constructed of a material selected from the group includingsteel, glass, aluminum, titanium, and graphite.

Preferably, the high-performance fibers are selected from the groupincluding aramid, ultra-high molecular weight polyethylene (UHMWPE),poly {p-phenylene-2,6-benzobisoxazole} (PBO), and poly {diimidazopyridinylene (dihydroxy) phenylene} (M5).

Preferably, the high-performance fibers comprise one or a combination ofthe following commercial synthetic fibers: Twaron®, manufactured anddistributed by Teijin Twaron® in Conyers, Ga.; Spectra Shield® PCR,manufactured and distributed by Honeywell International, Inc. ofColonial Heights, Va.; PBO Zylon®, manufactured and distributed byToyobo, Japan; and M5.

Alternatively, the fabric backing may comprise multiple layers includingone or a combination of Dyneema® UD75 HB2 unidirectional cross-pliedmaterial, manufactured and distributed by DSM of Greenville, N.C. andDSM of the Netherlands; and T-Flex™ unidirectional cross-plied material,manufactured and marketed by PTI Armor Systems of Glendora, Calif.

According to another preferred embodiment of the invention, the rigidfacing includes a generally flat, continuous monolithic plate. The platemay also have a slight single, double, or compound curvature.

Preferably, the rigid facing and fabric backing have a combinedthickness of less than 0.900-inches.

Preferably, the rigid facing and fabric backing have a combined weightof less than 5.1 pounds per square foot.

According to another preferred embodiment of the invention, the rigidfacing is constructed of a non-ceramic material selected from the groupincluding boron carbide, silicon carbide, titanium diboride, aluminumnitride, silicon nitride, sintered silicon carbide, sintered siliconnitride, and aluminum oxide.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the objects of the invention have been set forth above. Otherobjects and advantages of the invention will appear as the descriptionproceeds when taken in conjunction with the following drawings, inwhich:

FIG. 1 is a perspective view of a non-ceramic hard armor compositeaccording to one preferred embodiment of the present invention, andshowing a portion of the outer cover torn away to expose the interiorelements;

FIG. 2 is a cross-sectional view of the non-ceramic hard armor compositetaken substantially along line 2-2 of FIG. 1; and

FIG. 3 is a perspective view of a non-ceramic hard armor compositeaccording to a second preferred embodiment of the present invention, andshowing a portion of the outer cover torn away.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE

Referring now specifically to the drawings, a non-ceramic hard armorcomposite according to the present invention is illustrated in FIG. 1,and shown generally at reference numeral 10. In one application, thecomposite 10 is a small arms protection insert (SAPI) designed toprotect against multiple small arms bullets and projectiles. Thecomposite 10 is constructed according to United States militaryspecifications, CO/PD 00-03D dated Jan. 13, 2003, in sizes X-small,small, medium, large, and X-large ranging in weight from 2.85 to 5.35pounds. All SAPI sizes have a uniform nominal areal density of 5.1pounds per square foot or less. The dimensional measurements areindicated in Drawing Nos. 2-6-265, 2-6-266, 2-6-267, 2-6-268, and2-6-269 of CO/PD 00-03D. The entire subject matter of CO/PD 00-03D,including text, drawings, tables, and charts, is incorporated herein byreference.

As shown in FIGS. 1 and 2, the hard armor composite (SAPI) 10 comprisesa rigid non-ceramic plate 11 and ballistic fabric backing 12 encased inan outer cover 14. The cover 14 may be formed of a single knit material,such as nylon fabric, or may be a rubberized coating formed by dipping,or may be a combination of fabric, rigid plastic, and foam or honeycombstructure that protects the plate from wear-and-tear, and which containsany fragmentation upon impact as appropriate. Preferably, the cover 14includes a bake panel 15 that either partially or completely covers therear surface of the composite 10.

The plate 11 comprises a rigid, non-ceramic facing defining a firstlevel of hard armor protection in the composite SAPI. The rigid plate 11may incorporate any of the above-mentioned high-performance, low dpffibers combined with a number of individual non-ceramic elements, suchas S-2 glass fiber, carbon fiber, silicone-carbide, and graphite,arranged in either woven layers, non-woven unidirectional layers, orknit layers, or three-dimensionally knit or woven structures. Theresulting composite is either flat or molded to any desired rigid form.Although plate thickness may be varied to suit the specific SAPI need,the preferred structural arrangement ranges from 0.080-inches to0.40-inches in thickness.

The fabric backing 12 is bonded or otherwise secured, either directly orindirectly, to the rigid plate 11, and provides a second level ofprotection against ballistic penetration. Preferably, the rigid plate 11and fabric backing 12 are joined together by a layer 16 of adhesive,such as a thermoplastic or thermoset polymer, an elastomeric resinmatrix, or a film, such as epoxy, polyurethane, polysulfide, polyolefin,phenolic, polyester, vinyl ester, polyvinyl butyral.

The backing 12 is constructed of bundled, high-performance, low denierper filament (dpf) fibers comprising any one or a combination of aramid,extended chain ultra-high molecular weight polyethylene (UHMWPE), poly{p-phenylene-2,6-benzobisoxazole} (PBO), and poly {diimidazopyridinylene (dihydroxy) phenylene} (M5). Each of these fibers has atensile strength greater than 7 grams per denier. Suitable commercialfibers include: Twaron® micro-denier fiber of less than nominal 1000denier and 1.5 dpf or lower; Spectra Shield® PCR fiber of less thannominal 1300 denier and less than 5.4 dpf; Dyneema® UD (unidirectional)fiber of nominal 1600 denier and 2.0 dpf or lower; PBO Zylon® fiber ofnominal 1000 or 500 denier and 1.5 dpf or lower; and aramid Kevlar®fiber of nominal 1500 denier and 1.5 dpf. The fibers are preferably HM(high modulus) grade with low moisture content. The preferred embodimentutilizes high-performance fibers having less than 5.4 dpf, and morepreferably, less than 2.0 dpf, and most preferably, less than 1.5 dpf.In addition to the above, the backing 12 may incorporate othernon-ceramic elements, such as S-2 glass fiber, carbon fiber,silicone-carbide, and graphite.

The fibers are incorporated in multiple, stacked layers comprising knit,woven, or non-woven fabrics, non-woven or woven unidirectional tapes,felts, and three-dimensional structures. The stacked layers arelaminated under heat and pressure together with any of a variety ofpolymer compounds to create a dense, rigid, unitary ballistic structureranging in thickness from 0.130-inches to 0.350-inches. Laminationoccurs via autoclave, press molding, a resin transfer mold, and/or anoven with vacuum pressure. According to one embodiment, the fabricbacking 12 is further encased in a polymer matrix or film, specifically,a thermoplastic or thermoset matrix. The matrix may include any suitablepolymer resin or film, such as phenolic, polysulfide, phenolic,polyvinyl butyral rubber blends, polyester, vinyl ester, polyurethane,and polyolefin resins or combinations thereof. When using a polymerresin matrix, the preferred resin content ranges from fifteen totwenty-four percent by weight.

In an alternate embodiment shown in FIG. 3, the hard armor composite(SAPI) 20 includes an arrangement of individual non-ceramic tiles 21defining a rigid facing, an adhesive layer 22, and a ballistic fabricbacking 23. The tiles 21 can be square or otherwise shaped to suit thedimensional needs of a particular application. The tiles 21 may beformed of steel, glass, aluminum, titanium, graphite, or other suitablenon-ceramic material. The fabric backing 23 incorporateshigh-performance, low dpf fibers, and is constructed in a manneridentical to that described above. The adhesive layer 22 joins the tileelements and fabric backing together to form a unitary ballisticcomposite.

In each of the above embodiments, the hard armor composite 10, 20 formsa SAPI which meets or exceeds the ballistic performance criteriaoutlined in CO/PD 00-03D. Specifically, Section 3.9.3 of CO/PD 00-03Dstates that the SAPI when inserted in a nylon cordura carrier will becapable of defeating three impacts (2 impacts at 0-degrees obliquity and1 impact at 30-degrees obliquity) from each of the following threats:

a. NATO 7.62×51 mm-80 Ball at 2,750+50 feet per second.

b. Soviet 7.62 mm×54R Ball Type LPS at 2,300+50 feet per second.

c. U.S. 5.56 mm M855 Ball at 3,250+50 feet per second.

The use of a ballistic fabric backing incorporating high-performance,low dpf fibers not only reduces the overall weight of the composite, butoffers increased ballistic performance as compared relatively high dpffibers. The current commercial SAPI incorporates high-performance fiberswith a 5.4 dpf. The V50 ballistic performance of fabric constructed ofthis fiber is compared in the table below with fabric of lower dpffibers.

V50 data with 9 mm 124 grams per Mil-STD 662.

Dpf V50(fps) ADT(Areal density) psf UHMWPE fiber based fabric: SpectraShield ® 5.4 1590 .91 Dyneema ® UD 2.0 1679 .91 Aramid fiber basedfabric: Kevlar ® 29 1.5 1290 .80 Kevlar ® 29 1.5 1400 1.0  Twaron ® 1.01483 .87 Twaron ® 1.0 1562 .91 T-Flex ™ 1.0 1520 .80 T-Flex ™ 1.0 1590.93

A non-ceramic hard armor composite is described above. Various detailsof the invention may be changed without departing from its scope.Furthermore, the foregoing description of the preferred embodiment ofthe invention and best mode for practicing the invention are providedfor the purpose of illustration only and not for the purpose oflimitation—the invention being defined by the claims.

1. A hard armor composite, comprising: (a) a rigid non-ceramic facingcomprising high-performance fibers having a tensile strength greaterthan 7 grams per denier and at least one non-ceramic element, and saidhigh-performance fibers and said non-ceramic element being arranged in astructure selected from a group consisting of woven layers, non-wovenunidirectional layers, knit layers, a three-dimensionally knitstructure, and a three-dimensionally woven structure; (b) a ballisticfabric backing carried by said facing, and comprising an array ofbundled high-performance fibers, said fibers having a tensile strengthgreater than 7 grams per denier and a denier per filament ratio of lessthan 5.4; and (c) said rigid facing and fabric backing having a combinedthickness of less than 0.900-inches, and a uniform areal density of nomore than 5.1 pounds per square foot.
 2. A hard armor compositeaccording to claim 1, wherein said fabric backing comprises a pluralityof overlying fabric layers.
 3. A hard armor composite according to claim2, wherein said fabric layers are laminated under heat and pressure toform a unitary ballistic structure.
 4. A hard armor composite accordingto claim 1, and comprising means for adhering said fabric backing tosaid facing.
 5. A hard armor composite according to claim 4, whereinsaid means for adhering comprises an adhesive selected from the groupconsisting of a thermoplastic polymer resin matrix and a thermosettingpolymer resin matrix.
 6. A hard armor composite according to claim 4,wherein said means for adhering comprises a polymer film.
 7. A hardarmor composite according to claim 4, wherein said means for adheringcomprises an adhesive selected from the group consisting of an epoxyadhesive, a polysulfide adhesive, a polyurethane adhesive, a phenolicadhesive, a polyester adhesive, a polyvinyl butyral adhesive, apolyolefin adhesive, and a vinyl ester adhesive.
 8. A hard armorcomposite according to claim 1, wherein said high-performance fibers areselected from the group consisting of aramid, ultra-high molecularweight polyethylene (UHMWPE), poly {p-phenylene-2,6-benzobisoxazole}(PBO), and poly {diimidazo pyridinylene (dihydroxy) phenylene} (M5). 9.A hard armor composite according to claim 1, wherein said rigid facingcomprising a generally flat, continuous monolithic plate.
 10. A hardarmor composite, comprising: (a) a rigid non-ceramic facing comprisinghigh-performance fibers having a tensile strength greater than 7 gramsper denier and at least one non-ceramic element, and saidhigh-performance fibers and said non-ceramic element being arranged in astructure selected from a group consisting of woven layers, non-wovenunidirectional layers, knit layers, a three-dimensionally knitstructure, and a three-dimensionally woven structure; (b) a ballisticfabric backing carried by said facing, and comprising an array ofbundled high-performance fibers, said fibers having a tensile strengthgreater than 7 grams per denier and a denier per filament ratio of nomore than 2.0; and (c) said rigid facing and fabric backing having acombined thickness of less than 0.900-inches, and a uniform arealdensity of no more than 5.1 pounds per square foot.
 11. A hard armorcomposite according to claim 13, and comprising means for adhering saidfabric backing to said non-ceramic facing.
 12. A hard armor compositeaccording to claim 15, wherein said means for adhering comprises anadhesive selected from the group consisting of an epoxy adhesive, apolysulfide adhesive, a polyurethane adhesive, a phenolic adhesive, apolyester adhesive, a polyvinyl butyral adhesive, or a polyolefinadhesive, and a vinyl ester adhesive.
 13. A hard armor compositeaccording to claim 13, wherein said non-ceramic facing comprises agenerally flat, continuous monolithic plate.
 14. A hard armor compositeaccording to claim 13, wherein said high-performance fibers are selectedfrom the group consisting of aramid, ultra-high molecular weightpolyethylene (UHMWPE), poly {p-phenylene-2,6-benzobisoxazole} (PBO), andpoly {diimidazo pyridinylene (dihydroxy) phenylene} (M5).